Insulation break detector



Dec; 14, 1948.

D. SHAILOR I 2,456,453

INSULATION BREAK DETECTOR Filed March 20, 1944 INVENTOR.

DOUGLAS SHAI LOR ATTORNEYS Patented Dec. 1%, 1948 UNITED STATES PATENTOFFICE 1 iv g 3- 24g6"453 H I, v v INSULATION BREAK DETECTOR DouglasShailor, Detroit, Mich., assignor to-Briggs Manufacturing Company;Detroit; Mich., acorporation of Michigan v I. Application March 20, 1941, Serial No, 527,281; 1-

2 Claims. (01. 1754183) Y d The invention relates to means for detectingconductors Npassing through the conduit M may any break in theinsulation of an electrical conthen be successively tested by insertingthe bared ductor which might result in a short circuit; outer-end of oneof said conductors into the It is the object of the invention toobtain.a socket contact J afterwhich the "flexible casing portableconstruction which can be carried to the H is squeezed to close theswitch I. This will-close point where the conductor, to be tested islocated the primary circuit automatically-starting the and w i s p d d wt m a s for qu kly high frequency current interrupter and therebyperforming the test. For instance, in airplane inducing a high voltagepulsating current in the manufacture it is customary to draw insulatedsecondary circuit. This secondary circuit will conductors throughmetallic conduits installed 10 not, however, be closed unless there issome break in the plane and sometimes in so doing the insulain theinsulation of the conductor N which will tion may be broken at one ormore points thereby permit passage of current therethrough to theshort-circuiting the conductor on the conduit. conduit M. If this is thecase, then the induced It is an object of my invention to provide meanscurrent in the secondary circuit will illuminate for readily testingeither one or a plurality of the neon lamp which shows that theinsulation insulated conductors passing through a conduit is defective.On the other hand, if there is no to determine whether there are anyshort circuits. break in the insulation of the conductor N With theseobjects in view the invention consists through which current can pass tothe conduit in the construction as hereinafter set forth. M, then thesecondary circuit-will not be closed In the drawing I have mmaticallyrepreand, consequently, the indicator lamp E will not sented my improvedinsulation break detector as be illuminated. To show that the battery Ais used for successively testing a plurality of insuin operativecondition, a pilot light 0 is located in lated con Passing rough theSame a shunt circuit P between the terminals of said conduit, battery. Arheostat Q in the primary circuit A is a portable source of electricalcurrent such serves to regulate the ohmic resistance thereof. as astorage battery, B is a transformer having It is not necessary that theconductor N should aDrima-ry Winding a seeendary Wi di B be actually incontact with said conduit as the C is the circuit for the primarywinding and D induced current in the secondary current is of the circuitfor the secondary winding. In the sufllciently high Voltage t jump a, hrt ga,p o latter is located an indicator preferably a neon- 3 the otherhand, if th r i no b e k i th i l ype lamp E- F is a V b or or equ va nthigh tion then the secondary circuit will not be closed frequencycircuit breaker connected into the and the lamp will not be illuminated.The inprim y i G is a n ens r f r pro n strument is thus very sensitiveand will detect the contact points of said vibrator and H is a any breakin the insulation which might later probe. This probe H is provided witha flexible result i a, h rt i it,

outer casing formed of insulating material and Th storage battery d i itb k as pted to be g p y the hand of the p herein disclosed constitute agenerator which ator. Within this casing is located a switch I producespulsating current but the term generbiased to n rm y p but Which may beclosed ator as used in the claims may include any source by squeezingthe casing H. There is also-asocket of interrupted current used inconnection with contact J located in the nose of the casing. The th i tiprimary circuit C is extended into the probe I-I w t I claim as myinvention through flexible Conductors K and which are 1. An insulationbreak detector for insulated coupled to each other when the switch I isclosed. ele trica conductors comprisin an electric gen- One of theseconductors also forms a portion of erator f pulsating current, a t f r eoperathe secondary circuit which leads to the socket tively connected toSaid generator and having contact J. A flexible conductor L forminganprimary and secondary coils, a hand probe havother portion of thesecondary circuit is adapted ing a fl xibl casing a circuit closing t hto be grounded as, for instance, b connecting it within said casingbiased to open and a contact to the conduit M through Which the Wires tobe for electrical connection with an insulated contested a e d a ductorto be tested, a flexible connection between All of the parts thus fardescribed may be said. transformer and probe including a plurality mou tp a p a frame 0 carriage (not of electrical conductors forming portionsof both shown) so as to be movable to the point where primary dSecondary circuits of said t he t n is to e performed. The insulatedformer, the secondary circuit extending to said contact and said switchbeing in series with both primary and secondary circuits, a flexibleconductor for connecting the other terminal of said secondary coil witha conductor in proximity to the insulated conductor to be tested, and aneon lamp in series with said secondary circuit whereby pressure on theflexible casing of said probe will close said i' switch-andprimarwcircuit and will illuminate said lampzif the insulation oftheconductor is defective.

2. A portable insulation break detector for one or more insulatedconductors enclosed within a M conduit of conducting material,comprlsinge storage battery, a high stenup transformer operr ativelyconnected to said battery and: including in the primary circuit thereofa circuit breaker,

a hand probe having a flexible insulator casing,

a circuit closing switch within said casing biased to open, a contact atthe nose of said casing for electrical connection with any one of theinsulated conductors within said conduit, a flexible connection betweensaid transformer; and said probe including 79. plurality"v ofelectrical: confine-'- tors-for ccnnecting the primary circuit otwsaidtransformer to saidrswitch i towinclude the latter in said circuit andior also connecting onelead REFERENCES CITED Thesfoilowing" referencesare of record in the file of this patent.

UNITED" STATES PATENTS Number Name Date 974,712 Seyranian Nov. 1, 19101,561,483 Pi'ckard: -Nov. 1'1, 1925 1,919,802: Pi'eifieri' July 25;19331,950,484- Clarvoe Mar; 13, 1934.- 2,020,402: Fdwards et a] Nov. 12;1935 2,204,295 Brockman June 11, 1940 2367,4'i1.

Schwinn Jan. 16,1945

